Control method and device for low-temperature refrigeration operation of air conditioner and air conditioner

Abstract

The invention provides a control method and device for low-temperature refrigeration operation of an air conditioner and the air conditioner. The control method comprises the following steps that S2,after the air conditioner enters a low-temperature refrigeration mode, an outer fan is adjusted to the lowest rotating speed; S3, the inner coil pipe temperature TN is detected, the inner coil pipe temperature interval Q where the inner coil pipe temperature TN is located is judged and determined, and the compressor frequency corresponding to the current inner coil pipe temperature interval and anadjusting program of the rotating speed of the outer fan are obtained; S4, the outdoor unit outer coil pipe temperature TW is detected, and whether the TW is larger than an outer coil pipe preset threshold value T<outer coil pipe> or not is judged; S5, the adjusting program is executed according to the detected inner coil pipe temperature interval Q in which the inner coil pipe temperature TN islocated and information of the outdoor unit outer coil pipe temperature TW and the T<outer coil pipe>; and S6, the S3 or S4 is repeatedly executed after adjustment is finished. According to the control method for low-temperature refrigeration operation of the air conditioner, multi-section control is implemented according to the inner coil pipe temperature, the rotating speed and the frequency ofan outdoor unit are intelligently adjusted according to changes of the inner coil pipe temperature and the outer coil pipe temperature, graded operation is achieved, and operation is reliable and stable.

Description

technical field [0001] The invention relates to the technical field of air-conditioning equipment, in particular to a method and device for controlling low-temperature refrigeration operation of an air-conditioner and an air-conditioner. Background technique [0002] An air conditioner usually includes an indoor unit and an outdoor unit. The indoor unit is provided with an evaporator and an internal fan, and the outdoor unit is provided with a compressor, a condenser and an external fan. Usually, the commonly used air conditioner is only used when the external environment temperature is relatively high. When the outside temperature is lower than 28°C, the maximum operating frequency is set to avoid freezing of the evaporator of the indoor unit. [0003] In some special application scenarios, the air conditioner may also need cooling operation in winter or when the temperature is low. Take the computer room air conditioner as an example. Since a large amount of heat generate...

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Problems solved by technology

[0004] Special places require air conditioners to be used in low-temperature environments. In low-temperature environments, the cooling operation of the outdoor unit often results in better heat dissipation, resulting in low evaporation temperature, which is easy to cause low evaporation temperature, resulting in indoor unit freezing, which affects the cooling effect. The existing technology often Reduce outdoor heat exchange by reducing the frequency or reducing the speed of the outdoor unit

However, in low temperature environment, the viscosity of compressor refrigeration oil is high, and the low frequency operation causes the torque of the compressor to increase, reducing the service life of the compressor, and reducing the speed of the outdoor unit or stopping the control of the fan. Once the control is slow, the system pressure will exceed the standard. Further damage the compressor, reduce the service life of the compressor, reduce the reliability of the air conditioner in low temperature environment, and even cause the air conditioner to fail to cool normally in low temperature environment

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